The distribution of a sample of the outside diameters of PVC gas pipes approximates a symmetrical, bell-shaped distribution. The arithmetic mean is 14.0 cm, and the standard deviation is 0.1 cm. About 68 percent of the outside diameters lie between what two amounts?
A) 13.5 and 14.5 cm
B) 13.0 and 15.0 cm
C) 13.9 and 14.1 cm
D) 13.8 and 14.2 cm

Question

Quizplus · Accepted Answer

According to the Empirical Rule, approximately 68% of the data falls within one standard deviation of the mean. Since the mean is 14.0 cm and the standard deviation is 0.1 cm, one standard deviation below the mean is 13.9 cm and one standard deviation above the mean is 14.1 cm. Therefore, the outside diameters lie between 13.9 cm and 14.1 cm.

The Distribution of a Sample of the Outside Diameters of PVC